Method of and apparatus for charging rotating pipe-molds



J. B. LADD.

METHOD OF AND APPARATUS FOR CHARGING ROTATING PIPE MOLDS.

APPLICATION FILED NOV- 1. 1918.

1,351,767. PatentedSept. 7,1920.'

3 SHETSSHEET 1.

I. B. LADD.

METHOD OF AND APPARATUS FOR CHARGING ROTATlNfi PIPE MOLDS.

PatenteflSept. 7, 1920.

APPLICATION FILED NOV-1, 1918- 1,351,767.

3 SHEETSSHEET 2.

B. LADD. METHOD OF AND APPARATUS FOR CHARGING ROTATING PIPE MOLD'S.

Patented'Sept. 7,

3 SHEETS-SHEET 3.

APPLICATION FILED PIOV. 1, 191-8.

UNITED STATES PATENT oFiucE.

JAMES B. 'IJADD, 0F ARDMORE, PENNSYLVANIA, ASSIGNOR T0 UNITED STATES JAST IRON PIPE AND FOUNDRY COMPANY, OF BURLINGTON, NEW JERSEY, A CORPORA- Tron on NEW JERSEY.

METHOD OF AND APPARATUS To all whom it may concern:

Be it known that I JAMES B. LADD, a citizen'of the'United States of America, and a resident of Ardm'ore, in the county of Montgomery, in the State of'Pennsylvania, have invented certain new and useful Improvements in Methods of and Apparatus for Charging Rotating Pipe-Molds, of which the following is a true and exact description, reference being had to the accompanying drawing, which forms a part thereof.

The general object of the present invention is to provide an improved method of, and apparatus for supplying molten casting metal to elongated horizontal rotating molds of centrifugal casting machines, and particularly to centrifugal casting-machines for formin relatively large size cast iron pipe. Heretofore it has been the practice to charge molds of centrifugal pipe casting machines with molten metal by feeding the metal simultaneously and with substantial uniformity all along the length of the mold, the typical mold charging; device heretofore used being a trough, axially disposed in the mold and rotated to empty-into the mold the charge of molten metal contained in the trough through a discharge orlfice, or over a discharge lip, running substantially the length of the mold.

The construction and manipulation of such a rotatable trough mold char ing device isnot a simple matter, and (llifiClllty is experienced in keeping the trough in operative condition, and particularly in preventing substantial and disturbing accumulations of solidified charge forming metal on the surfaces of the trough. In proceeding in accordance with the present invention, the mold is'not charged with molten metal simultaneously along the length of the mold, but progressively from one end of the mold to the other. To accomplish thisprogressive charging of the mold it is necessary, of course, to complete the charging of the mold in a very short period of time, in order to insure a casting of uniform'thickness and of homogeneous character. The length of the period in which the charging operation must be completed depends, of course, upon the length and weight of the casting formed and also upon the character of the mold. In

Specification of Letters Patent.

FOR CHARGING ROTATING PIPE-MOLDS.

Patented Sept. '7, 1920.

Application filed November 1, 1918- Serial forming an ordinary cast iron pipe in a mold in which the wall of the mold cavity is formed of metal, the charging period will ordinarily be a matter of a second or two. In forming a similar casting in a sand lined mold, the duration of the charging operation may be substantially greater, but with such a mold the charging period will ordinarily be a matter of comparatively few seconds.

In practice my invention, considered in its broader aspects, comprises two general modes of operation. In one of these modes the molten metal is discharged into one end of the rotatin axial jet, and t e velocity of the jet stream 1s progressively ,varied as required to promold in the form of an gressively distribute the molten metal along the length of the mold. In the second mode of practising my invention the mold is charged through a conduit discharging at one end, which projects intothe. mold and is moved axially therein to distribute the stream of molten metal flowing through it at a relatively low velocity, along the length of the mold. This mode of charging the mold is particularly...adapted: for use in charging pipe molds only when the latter matter in which I have illustrated and described preferred forms of mechanism and preferred methods used in practising my invention.

Of the drawings: 7

Figure 1 is a diagrammatic elevation of mold casting apparatus comprising means for charging a mold by a jet of molten metal of varying velocity. p

Fig. 2 is a sectional elevationof a portion of the apparatus shown in Fig. 1.

Fig. 3 isa view taken similarly to Fig. 2', 1

illustrating a modification of the apparatus shown in Figs. 1 and 2.

apparatus shown in Fig. l.

-- shown in Fig. 6.

Fig. 8 is an end elevation, partly in section, illustrating still another type of apparatus for charging a mold by a jet of vary- 7, ing velocity.

Fig. 9 is a plan, in section on the line 99 of Fig. 8.

Fig. 10 is a sectional elevation, diagram-f matic in character, illustrating apparatus for charging the mold through a conduit extending into, and axially movable in the mold.

Fig. 11 is a section illustrating a modfication of a portion of the apparatus shown in Fig. 10.

Fig. 12 illustratesa modification of the type of apparatus shown in Fig. 10, and

Fig. 13 represents a second modification of the type of apparatus shown in F1g..10.

The apparatus shown in Figs. 1,2, t and 5 comprises a rotating metal mold A, which may be supported and rotated by any usual or suitable means, not illustrated herein, as they form no part of my present'invention. B" represents a molten metal 'IQSGIVOlI or charging ladle, which is shown as formed with a discharge passage B open to the interior of the receptacle B at the bottom of the latter, and terminating at its outlet end in a horizontal portion, from which the molten metal passes into a nozzle C detachably secured to the receptacle B and axially disposed with respect to the mold A. j The mold A, shown in Figs. 1 and 2, is a metal mold and by the term metal mold, as used herein, I mean a mold having the wall of the mold cavity formed wholly or largely of metal. The nozzle C has its discharge end barely inserted in the mold A, as shown in Figs. 1 and 2. When the mold hasa san'd lining A as does the mold AA, shown in Fig. 3, the nozzle C may be replaced by a nozzle CC, having its "bore substantially largerthan the bore of the nozzle C, because of the lower jet velocity permissible with a non-metallic mold. The nozzle CC advantageously projects into the mold an appreciable distance, as shown in Fig- 3, during a portion of the mold charging operation.

The receptacle B is provided with an inlet B at its upper end for compressed air for expelling the molten metal from the receptacle through the dischargepassage B? of the charging operation. scale comprises twobeams D and D, both of which are elevated by the weight on'the.

and nozzle C or CC at the desired velocity. As shown, the receptacle B is formed with a filling opening, sealed during the mold charging operation by a movable cover 13. The receptacle B is provided with trunnions B for mounting the receptacle on a suitable support so as to permit the receptacle to be tilted in filling and emptying the .same, though it is to be understood that in charging a mold in-accordance with the present invention, the receptacle B will ordinarily not he tilted-during the mold charging operation.

As shown in Figs. 1 and the support in which the trunnions B are journaled is a frame or bracket D carried by the platform of a weighing scale D, which, as shown, is-mounted on wheels D, running along stationary track rails E. The scale D is connected to the plunger of a fluid pressure motor cylinder F by means of which the scale may be moved to carry the receptacle B into and out of the mold charging position preparatory to, and at the end-of a mold charging apparatus; and, in the case of the sand lined mold arrangement of Fig. 3 maybe moved to carry the nozzle CC out of the mold cavity during the final portion The platform scale platform at the beginning of the mold charging operation, but are depressed on the decrease in weight of molten metal in the receptacle B. occurring as the mold chargmg operation proceeds. The scale mechanism is so arranged that the beam D will be depressed in an early stage of the mold charging operation, while the lever D will 'not be depressed until the mold charging operation is practically completed. The depression of the lever D is relied upon to automatically vary the jet velocity with which the molten metal is forced out of the receptacle B and discharged into the mold, and the depression of beam D stops the discharge of molten metal. As shown in'Fig. 1, on the depression of the beam D which, as already stated, occurs during an early stage in the mold charging operation, the beam engages an electrical control G. This closes an electric current, including contact G, scale beam D electric supply conductors land 2,- and the magnetizing winding of an electromagnet H. The energization 'of theelectromagnet Hcauses the armature H of the latter to move to the right, as shown in Fig. 1. The armature H is-connected by alink to the operating lever I of a th-rottle'valve I in a compressed air supply pipe I. To insure a prolonged closing movement of the throttling valve I at the r the receptacle when depressed,

' air supply conduit I.

shown as also provided with an automatic- H The latter has its opposite ends connected by a by-pass H in which is located a regulating valve H The scale beam D, engagesa contact GA and thereby closes an electric circuit, including conductors 3 and 4, a contact GA engaged by the scale beam D6, and-the winding of an electromagnet HA. The armature of the latter is connected by a link to the operating arm of a cutoff valve IA in the compressed Y The conduit I is pressure regulating valve J at the inlet sides of the valve I and IA. The pressure supply pipe 1 is connected at the outlet sides of the valves to the compressed air inlet B of the receptacle B by a flexible pipe section I, which permits the necessary movement of the receptacle B by the cylinder F, without requiring any movement of the compressed air supply pipe I. It will be understood, of course, that the conductors 1, 2, 3 and 4 should include flexible portions for the same purpose.

In operation, after the apparatus is brought into condition for charging the mold A, with the latter in rotation, and with B containing a suflicient amount of molten metal, and having its discharge nozzle C properly entered inthe end of the mold, the previously closed valves I and IA, one atleast of which was previously closed, are then both opened. In "this initial charging condition of the apparatus both scale beams D and D are up and the electromagnets H and HA are deenergized. As soon as the valves IA and I are opened compressed air passing through the conduit 1 quickly builds up the pressure in the top of the receptacle B to a maximum fixed by the pressure regulating valve J. The pressure thus obtained,in the top of the receptacle B forces moltenmetal out of the receptacle B through the outlet passage B and nozzle C. The velocity of the issuing jet will be the function of the pressure in the upper portion of the receptacle B, and should be suflicient to cause the jet to carry to the rear end of the mold where it impinges against the disk A carried by the end member A of the mold. After a small portion of the amount of metal necessary to charge the mold has been expelled from the receptacle B, the decreased weight of the latter permits the scale beam D to drop into engagement with the contact G, and thus energize the electromagnet H, whereupon the throttling valve I begins to close. As the throttling valve I closes, the pressure maintained in the upper end of the receptacle B decreases, producing a corresponding reduction in the velocity of the jet stream, so that the latter drops short of the far end of the mold, and as the pressure in the receptacle B continues todecrease, as

the valve I continues to close, the jet stream becomes shorter and shorter until finallyit just clears the nozzle C. When the mold is the magnet H is energized may be varied,

of course, by adjusting the bypass valve H Any fall in liquid metal level in the receptacle B as the mold charging operation proceeds tends of itself to decrease the velocity of the .jet stream, but this tendency 1s not substantial unless the horizontal cross section of the receptacle is small enough so that a very considerable decrease in weight of the molten metal level occurs in charging a single mold. It will be understood, of course, that after the receptacle B has received its charge of molten metal and the cap B is put in place the weights on the scale beams D and D are adjusted to insure the successive depression of those beams after the proper weights of molten metal shown in Fig. 3, is used with a sand lined mold AA, the cylinder F may be manipulated to slowly withdraw the nozzle, CC from the mold during all or the final portion of-the pouring operation.

In Fig. 6 I have illustrated a very simple form of mechanism for use in obtaining an automatically graduated jet stream velocity of the molten metal charged into the mold AA, shown in that figure. The mold charging. apparatus shown in Fig. 6, comprises standplpe BB, having a curved portion B at the bottom which terminates in a horizontal nozzle adapted to project into the end of the mold. The standpipe BB, as shown, is mounted on a carriage L movable toward and away from the mold on suitable track rails by means of the cylinder F, having its plunger F connected to the carria e L. With the apparatus shown in Fig. 6 t e 'velocity of discharge is determined by the head of the molten metal column in the conduit BB. The molten metal is poured from a suitable ladle, not shown, into the top of the column BB rapidly enough so that the colunm will fill to its upper end before more than a 'small portion of the molten metal has had time to be discharged into the mold through the restricted nozzle orifice. Wlth thisarrangement a small portion of the charge is supplied to the mold progressively along its length from its end adjacent the column BB to the opposite end as the head in the column BB builds up, and then, as the head of molten metal in the column BB decreases, the mold is charged progressively from its remote end to its charging end. The nozzle B may be made longer and slowly withdrawn from the mold during all or the final portion of the pouring operation. In the modification of the apparatus of Fig. 6, shown in Fig. 7, the body portion of the column BC is separated from the curved nozzle portion B by a valve controlled port B Flow through the port B is con rolled by a stopper like valve M, which extends up through the column BC, and has a. down-turned portion outside of the column connected to an operating lever M. The latter is pivotally connected to the standpipe BC. With this apparatus the proper charge of molten metal may be )ut into the standpipe BC while the port is closed by-the valve M; when the latter is opened wide, the molten metal is discharged with an initial velocity high enough to carry it to the remote end of the mold.

As the head of molten metal in the column BC decreases, the jet velocity decreases, and the desired progressive discharge along the length of the mold is thus obtained. It will be understood, of course, that the horizontal by the discharge of successive equal portions of molten metal, or nozzle B may be made longer as shown in dotted lines and indicated at 6 in Figs. 6 and 7, and slowly withdrawn from the mold during all or the final portion of the pouring operation.

In the modified form of apparatus shown in Figs. 8 and 9, a receptacle ED is employed, which is pivotally connected to its supporting carriage L, so that the receptacle may be swung from the horizontal position shown in full lines in Fig. 8 into the nearly vertical position shown in dotted lines in that figure. As shown, the nozzle portion B" of the receptacle BD, which extends at right angles to the length of the body portion of the receptacle, is journaled in the bearing L provided in the carriage L second coaxial trunnion like extension B of the receptacle BD coaxial with the nozzle B is journaled in a second bearing L pro vided on the carriage L. A cable L connected to the receptacle BD, at one end, and

during all or the final L. The molten metal for char ing a mold.

AB, is put into the receptacle B D when the latter is in the position shown in full lines in Fig. 8. The upper surface level of the molten metal in the horizontally disposed receptacle BD when filled, is below the discharge passage B through the nozzle portion B. When motive fluid is supplied to the cylinder L and the pulley L is drawn down, the receptacle BD is turned from the full line-position into the dotted line position of Fig. 8. This causes the molten metal content of the-receptacle BD to be discharged through the nozzle B with a jet velocity at any instant which will depend upon the height of liquid level in the body of the receptacle BD above the discharge orifice B" length of the mold may be secured, or, as

before noted, the nozzle B may be made longer as indicated at b in dotted lines in F 1g. 9 and slowly withdrawn from the mold portion of the pouring operation.

The apparatus shown somewhat diagrammatically in Fig. 10, for charging the sand lined mold AA, comprises a conduit 0, shown as a trough having an open end. At the beginning of the mold charging operation proper, a portion or the conduit 0, which is longer than the mold, is axially disposed in the mold extending from the charging end to the'opposite end of the mold, where the open end of the conduit abuts against, and is temporarily closed by a stop plate or valve member Q carried by a stem Q, splined in a sleeve carried by a bracket Q? and in threaded engagement with a nut Q swiveled in the bracket sleeve and supplied with molten metal. The project-- ing outer end of the conduit 0 is mounted on a carriage LA sliding along a guidcway L parallel to the length of the mold AA.

The carriageLA is connected to the plunger or piston rod of a fluid pressure motor cylinmay be withdrawn from the mold AA at 5 any desired rate.

- With the apparatus shown i111; Fig. 10 the' desired progressive charging of the mold AA, along the length of the lfatter, is obtained by manipulating thel l valve F to withdraw the conduit A froih the mold at theproper velocity. As the conduit O is drawn out of the mold, the molten metal be- .gins to discharge as soon as the end of the conduit is opened by its movement away from the plate Q. The manner in which the molten metal is distributed along the length of the mold will obviously depend upon the rate at which the conduit 0 is withdrawn from the mold. In Fig. 11 I have illustrated apparatus in which the stop plate QA, corresponding in function to the plate Q previously described, is journaled in the end member A closing the bellend of the mold AA.

In Fig. 12 I have illustrated a modification of apparatus of the general type shown in F i 10 in which the portion of the conduit A, projecting out of the mold at the beginning of the mold char ing operation, is of considerable length an in which this conduit is intended to be empty at the beginning of the mold charging operation. The proper quantity of molten'metal for charging the mold AA in Fig. 12 is supplied to the conduit OA through the ladle PA continuously during the mold charging operation in the course'of which the conduit O is gradually withdrawn fromthe mold. To move the conduit OA into and out of the mold I have provided in Fig. .12 a rack gear at the under side of the outer portion of the conduit, which is engaged by a spur gear R journaled on a supporting bracket R and rotated by any suitable means which I have not thought it necessary to illustrate. Adjacent the mold the conduit OA is supported on a roller R journaled on a bracket R 1 V In Fig. 13 I have illustrated apparatus possessing some of. the characteristics of the apparatus shown in Fig. 10, and some of the characteristics of the apparatus shown in Fig. 1. In the apparatus shown in Fig. 13 the conduit OB employedis substantially identical with the conduit O of Fig. 10, but in this case, as in Fig. 12, the discharge end of the conduit OB is always open. The conduit OB is carried by the platform of a scale DA having wheels D running along track rails E as in Fig. 1. The scale DA is connected to the piston rod or plunger of a motor pressure cylinder FA. Also mounted on the platform of the scale DA is a -molten metal receptacle BB, having a bottom discharge port 13 which may be closed by a 'alve member MA connected to an operatlnglever M. The latter is connected to,

and operated by the armature of an electromagnet S in such fashion 'as to automatically close theport B when the scale lever D is depressed and engages the contact G forming a part of the energizingcircuit of the electromagnet S. The valve F controlling the operation of the motor cylinder FA is automatically operated by an electromagnet SA, which is energized when the scale beam D engages the contact Gr forming a part of the energizing circuit of the electroma net SA. The rate at which the conduit 0 is withdrawn from the mold when the valve F is turned to produce such withdrawal, is regulated by an adjustable throttling valve F in the motive fluid exhaust conduit F".

The apparatus of Fig. 13 is shown in condition for starting the mold charging operation Whenever the lever M is manually actuated to open the port B l/Vhen the port B opens molten metal begins to pass from the receptacle BB into the conduit OB. On the diminution in the weight of molten metal held in the receptacle BB occurring during the interval required for the molten metal to flow from the receptacle BB into the conduit OB, and out of the latter, is an amount suflicient to supply all or a portion of the metal required in the bell portion of the pipe being cast, the scale beam D is de-. pressed. This energizes the electromagnet SA and shifts the valve F to cause the withdrawal of the conduit OB from the mold. The metal continues to discharge from the receptacle BB into the trough OB as the latter is withdrawn from the mold, until the decrease in wei ht of the molten metal in the receptacle B permits the scale beam D to engage the contact G".- This energizes the electromagnet S and closes the port B While in accordance with the provisions of the statutes I have illustrated and described the best forms of apparatus for, and the best modes of practising the invention now known to me, it will be apparent to those skilled in the art that changes in the apparatus and methods illustrated and described may be made' without departing from the spirit of my invention as set forth in the appendedclaims, and that in some cases some features of my invention may be used to advantage without a corresponding use of other features of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The method of makin a tubular metal casting in an elongated mo (1 rotating about a horizontal axis, which consists in supplying'the molten casting metal to the mold in a jet and progressively varying the jet veloc-' length of molten metal is discharged intothe moldand means for varying the pressure by which the molten metal is forced through said nozzle.

3. In a centrifugal casting machine, the combination with a moldrotating about a horizontal axis, of mold charging means comprising a molten metal containing receptacle having a nozzle outlet adapted to v discharge a streamof moltenmetal'into said mold and means automatically responsive to the'change inweight of the metal in said receptacle occurring as the charging operation proceeds for causing the molten metal I stream to impinge against the wall of the mold cavity progressively along the length of the mold.

4. In a centrifugal casting machine, the combination with a mold rotating about a horizontal axis, a molten liquid receptacle having a nozzle outlet at its bottom adapted to discharge astream of molten metal into the mold, said receptacle being so vertically elongated and horizontally restricted that the change in head of molten metal occurring in a single mold charging operation Will cause the jet to impinge against the wall of the mold cavity progressively along the length of the mold during the mold charging operation.

JAMES B. LADD. 

